In both the Jacquard and spool Axminster looms a row of tufts for a complete row of the carpet is created simultaneously and transferred to the weaving point at which they are woven into a backing to produce the carpet.
A different approach to yarn tuft formation is described in WO 95/31594. Tufts of yarn to form a row of the carpet are produced by first loading yarn tufts into a yarn tuft holder by traversing the tuft holder stepwise through a sequence of loading positions so as to temporarily present predefined tuft retention sites of the tuft holder to each of a plurality of stationary tuft forming units. At each loading position one or more tufts are loaded into the sites by the tuft forming units until the tuft holder is loaded with tufts for a complete row of the carpet. The tufts are then transferred from the tuft holder to the weaving points simultaneously by means of grippers. Since the grippers do not perform the tuft formation, tuft formation can take place at the same time as the weaving operation and thus tuft formation can take place substantially continuously throughout the operation of the loom. This is to be contrasted with the conventional spool or gripper type looms where tuft formation takes place over only about half of each weaving cycle.
A yet further approach to yarn tuft formation is described in WO 02/00978. The loom includes one or more tuft forming units each of which includes a yarn selector wheel which typically holds 12 or 24 yarns of different colour. A motor drives the yarn selector wheel into one of a number of angularly discrete positions to select yarn of a predetermined colour. As the or each tuft forming unit traverses the loom relative to a stationary yarn tuft holder, tufts of predetermined colour are placed in tuft retention sites of the tuft holder. When the tuft holder is loaded with tufts for a complete row of the carpet, the tufts are transferred from the tuft holder to the weaving points simultaneously by means of grippers.
The yarn tuft holders of the prior art may take many different forms for securely holding each tuft. The tuft holder may be rigid and the profile of each slot defining a tuft retention site may be shaped such that the inherent elasticity of the tuft holds the tuft at the bottom of the slot when pressed therein. Alternatively, one or both opposing sides of each slot may be formed of a resilient material capable of gripping a tuft presented into the slot. Yet further, the sides of each slot may be rigid and a resilient clip may be provided to hold the tuft in place.
A problem associated with the yarn tuft holders of the prior art is that the position of the yarn tufts in the holder, and transfer of the tufts therefrom by the grippers, cannot always be accurately controlled. Unless all of the tufts are positioned correctly in the loaded tuft holder and all of the grippers can securely transport all of the tufts from the tuft holder to the weaving points, the grippers may transfer some of the tufts to the weaving points incorrectly or fail to transfer them at all. This can lead to a requirement for longer tufts so that these can be more readily gripped by the grippers resulting in increased yarn wastage. Any transfer failures can lead to downtime of the loom, and/or necessitate post production rectification of any flaws in the carpet.
There is therefore a need in the art for an improved yarn tuft holder which alleviates the above problems.